The present invention relates to devices and methods for exercising eyes.
Vision is the primary navigational system of a human body, providing 80 to 90% of all information received during a person""s lifetime. The proficiency of the vision skills affects every human activity and affects human performance on all levels. However, the human vision system functions in a more and more difficult environment as educational and occupational demands continue to grow exponentially in today""s society.
The United States economy, as well as that of many foreign countries, have moved from an industrial era to a service era and has entered the information age. More and more, a worker""s performance depends on gathering and internalizing a growing body of information in educational, occupational, and even social surroundings.
The computer has become a principal channel for providing services and information. There is an ongoing and dramatic rise in the number of people who use computers at work, at home after work hours, while shopping, reading the newspaper, and the like. The volume of services and information provided via computers also continues to increase. The explosive growth in the use of computers and other vision-related information-gathering activities dramatically increases demands on the vision system.
The visual system and its primary instrument, the eyes, do not respond well to this increased demand. The eyes are meant to respond effortlessly to images of objects that enter awareness and call for attention. However, it is unlikely that the eyes were designed to be used primarily for reading or working on a computer. Yet, as already discussed above, the educational and occupational requirements lead people to do just that.
As a consequence, modern society suffers from a virtual epidemic of vision problems, especially myopia. Such vision problems, including myopia, can be directly related to the amount of time spent reading or working on a computer. The educational system, with its major focus on visual information transmission and communication, is a major contributor to the epidemic.
The eyes are complex neuro-optical systems of the human body. They locate, track, and focus on objects of interest. Before describing the structure and functioning of the eyes, it is useful to describe certain aspects of inanimate optics and related physical phenomena.
A human eye perceives electromagnetic radiation in a certain narrow range of wavelengths (xcx9c400 nm to xcx9c700 nm), which may be referred to as the visible range. For the most part, the light perceived by the eye as images of various objects includes mixtures of light waves with different wavelengths. Thus, white light is a mixture of light waves of essentially all wavelengths in the visible range. The electromagnetic waves with unique wavelengths within the visible range (monochromatic light) are perceived as colors. For example, the monochromatic light with the wavelength of 660 nm is perceived as red and the light with the wavelength of 470 nm as blue. Various combinations of light waves (e.g., additions or subtractions) may also be perceived as colors.
On the basis of human perception of colors, the visible range is often divided into various color sub-ranges. One commonly described classification divides the visible range into violet, indigo, blue, green, yellow, orange, and red color sub-ranges:
Another classification divides the visible range into blue ( less than xcx9c490 nm), green-yellow (xcx9c490-590 nm), and red ( greater than xcx9c590 nm) sub-ranges. It should be noted that the boundaries between the color sub-ranges are approximate and depend on many factors. For additional discussion of human perception of color, see J. Liberman, Light: Medicine of the Future, Bear and Co., 1991.
Light interacts with material substances. Thus, light may change direction when passing through material substances, a phenomenon known as refraction. An index of refraction (n) measures the magnitude of refraction for a given substance. The index of refraction of a substance is the ratio of the velocity of light in a vacuum (C) to the velocity ("ugr"xcexd) of the light wave with a particular wavelength (xcexd) in the substance: n=C/"ugr"xcexd. The velocity of light in a vacuum is constant. However, in material substances, the velocity of light is different for each wavelength xcexd. Therefore, the index of refraction is different at different wavelengths. For this reason, light waves of different wavelengths (colors) are refracted by different amounts through the same optical element. The index of refraction increases as wavelength decreases, and therefore colors of shorter wavelengths exhibit greater change in direction in material substances than colors of longer wavelengths.
The refraction of light is used in various optical systems, such as prisms, lenses, and the like, to manipulate light in a desired manner. A lens is an optical system bounded by two refracting surfaces having a common axis. Lenses refract and focus light emitted by or reflected from various objects. Each lens has a characteristic focus point and focal length, which are commonly used to describe lenses (FIG. 1). The focus point is a point at which the lens focuses light from an object located at an infinite distance from the lens.
Referring to FIG. 1, F1 is the focus point of the lens L1, and F2 is the focus point of the lens L2. The focal length or focal distance (f) is the distance from the center of the lens to its focus point. In the examples of FIG. 1, f1 is the focal length of the lens L1, and f2 is the focal length of the lens L2. The focal length f determines the properties of a lens with respect to focusing of light.
FIG. 2 illustrates how lenses focus light from an object. As seen in FIG. 2, the lens L captures light from an object located at a point Q. The light is focused into an image of the captured object at a point Qxe2x80x2. The point Q is known as the object point and the point Qxe2x80x2 as the image point. S denotes the distance from the object point Q to the lens L, and Sxe2x80x2 denotes the distance from the lens L to the image point Qxe2x80x2.
For an ideal lens, one expression of the relationship between the focal length f and the distances S and Sxe2x80x2 is the thin lens equation: 1/S+1/Sxe2x80x2=1/f. If the object point Q is located at an infinite distance from the lens L (i.e., S is infinity), the term 1/s approaches zero and the image distance Sxe2x80x2 is equal to the focal length of the lens L. If the object distance S is less than infinity, the distance Sxe2x80x2 varies as a function of the distance S. Generally, for a given wavelength, the focal length f is fixed for a given inanimate lens. The term 1/f is also fixed for a given lens. Thus, the term 1/f is a parameter of the functional variation between the terms 1/S and 1/Sxe2x80x2 (and therefore the distances S and Sxe2x80x2). The term 1/f is known as the focusing power of the lens. The focusing power is measured in diopters, which is a metric unit equal to 1 divided by the focal length of the lens, in meters (1 diopter=1 mxe2x88x921). The shorter the focal length f of the lens, the greater the focusing power 1/f.
If the thin lens equation is applied to two different lenses with different focusing powers, the images of objects located at the same distance S are expected to be formed at different image distances Sxe2x80x2. Referring again to FIG. 1, the focal length f2 of the lens L2 is greater than the focal length f1 of the lens L1, and thus the lens L2 has more focusing power than the lens L1. As seen from FIG. 1, the greater the focusing power of the lens, the closer to the lens the captured image is formed.
As explained above, the index of refraction (n) varies with the wavelength, and therefore, for the same lens, the magnitude of refraction is different for light of different wavelengths (colors). Thus, the focal length of the same lens is different for different colors. As a consequence, a single lens forms not one image of an object, but a series of images at varying distances from the lens, one for each color present in the light emitted or reflected by the object. If the lens captures monochromatic light, an observer placed at the focus point of the lens perceives the image as sharp. However, if the captured light is not monochromatic, some of the constituent light waves may remain unfocused. This phenomenon, known as chromatic aberration, is illustrated in FIG. 3.
Referring to FIG. 3, the lens L captures non-monochromatic light from an object AB. Suppose, the light from the object AB includes light waves having wavelengths xcexd1 and xcexd2 (light waves xcexd1 and xcexd2), where xcexd1 less than xcexd2. Since the index of refraction is greater for shorter wavelengths, the lens L changes the direction of the light wave xcexd1 more than the direction of the light wave xcexd2. Therefore, the focal length of the lens L is smaller for the light wave xcexd1 than for the wavelength xcexd2.
The image for the light wave xcexd1, shown as Axe2x80x2Bxe2x80x2, is formed closer to the lens L than the image for the light wave xcexd2, shown as Axe2x80x3Bxe2x80x3. For example, if the wavelength xcexd1 is in the violet color sub-range and the wavelength xcexd2 is in the green color sub-range, the violet image would be formed closer to the lens L than the green image. The variation in the image distance as a function of color is called longitudinal chromatic aberration. The difference in the index of refraction at different wavelengths also affects the size of the image. The variation in the image size as a function of color is known as lateral chromatic aberration. In FIG. 3, the distance a measures the longitudinal chromatic aberration, and the distance b measures the lateral chromatic aberration.
Because of chromatic aberration, the same focus point is not optimal for all colors that comprise the light captured through the lens. Some colors will be perceived as sharp at the focus point of the lens, while others will not. The unfocused colors may form a fuzzy ghost image around the focused image.
As will be explained in more detail in the description of the invention, chromatic aberration may occur in a human eye, which, like inanimate optical systems, includes light-refracting elements. The structure of the eye is schematically illustrated in FIG. 4. Among the major parts of the eye are a cornea 2, an iris 4, a retina 6, an eye crystalline lens 8, a ciliary body 10, and ciliary zonules 12.
The cornea 2 is a transparent membrane that protects the eye from the outside world while allowing light to enter the eye. The iris 4 controls the amount of light that enters the eye by opening or closing a pupil, the variable aperture of the eye. The variations in the size of the pupil allow the eye to function over a wide range of light intensities. Thus, the pupil contracts to limit the amount of light in a bright environment, and fully opens in a dim light. The pupil also contracts for near vision, increasing the depth of field to improve perception of objects located in close proximity to the eyes.
The retina 6 is a thin sheet of interconnected nerve cells, which function as detectors, converting information carried by the light (images) into electrical impulses. The detecting elements of the retina 6 include rods and cones. The cones function primarily in normal lighting condition, while the rods are most effective in dim lighting. The sensitivity of the retina is different for different wavelengths within the visible range. The retina is most sensitive in the middle of the visible range, specifically in the green/yellow color sub-ranges, and least sensitive at both ends of the visible range, namely in the red and blue sub-ranges. The spectral sensitivity is also different for rods and cones. Thus, the peak of spectral sensitivity in normal lighting conditions (cone vision) is approximately 555 nm. In dim lighting (rod vision), the peak of sensitivity is approximately 510 nm. The retina is connected to the optic nerve that carries the information gathered by the eye to the brain. When light enters the eye, the crystalline lens 8 projects an inverted image on the retina 6.
The crystalline lens 8 is a transparent convex-shaped structure that focuses the light entering the eye to form a clear image on the retina 6. If the focus point of the crystalline lens 8 is on the retina 6, the perceived image is sharp. If the focus point is in front of or behind the retina, the sharpness of the image may suffer. The phenomenon of chromatic aberration observed in the inanimate optical systems also occurs in the eye. Nevertheless, in most circumstances, all colors are perceived as sharp to an observer because of various compensating mechanisms of the eye.
The crystalline lens 8 is attached to the ciliary body 10 by way of the ciliary zonules 12. The ciliary body 10 contains a ciliary muscle. The eye crystalline lens 8, the ciliary body 10, and the ciliary zonules 12 work together to keep the images entering the eye in focus.
The ability of the eyes to focus clearly on a target of interest at any distance is called accommodation. It is one of the most important visual skills. Although the thin lens equation (1/S+1/Sxe2x80x2=1/f) applies to ideal inanimate lenses, its general principles are helpful to describe the accommodation function of the eye. With respect to the thin lens equation, the focusing power of the eye is 1/f, the distance to an observed target is S, and the distance from the eye lens to the image of the target is Sxe2x80x2. As described, an image is sharp if it is focused on the retina. The distance between the crystalline lens and the retina is essentially constant. Thus, the distance Sxe2x80x2 between the crystalline lens and the image must also be kept essentially constant regardless of the target distance S, which continuously changes as a function of the environment. Applying the thin lens equation, the term 1/Sxe2x80x2 remains constant, the term 1/S is changing, and therefore, the term 1/f must change with the change in the distance S to maintain the sharpness of the image. The essential mechanism of accommodation therefore involves changing the focusing power of the eye. The smaller the distance to the observed target, the greater the required focusing power of the eye.
A normal eye does not require any increase in the focusing power in order to clearly see a target at 20 feet or beyond. The table below illustrates a useful non-limiting example of the relationship between the distance from an eye to a target of observation and the required focusing power for a normal eye (in diopters):
Referring to FIG. 4, the change in the focusing power of the eye lens 8 is accomplished by changing the shape of the lens 8 with the help of the ciliary body 10 and the ciliary zonules 12. If the observed target moves closer, the ciliary muscle of the ciliary body 10 constricts thereby causing the zonules 12 to slacken and allowing the crystalline lens 8 to bulge. The resulting increase in the convex cross-section of the crystalline lens 8 increases its focusing power. If the observed target moves away from the eye, the ciliary muscle relaxes, tightening the zonules 12, and flattening the lens 8, thereby reducing the focusing power of a normal eye. At the distance of more than 20 feet, the ciliary muscle is usually relaxed.
In addition to accommodation, other essential visual skills include fixation (the ability to accurately aim the eyes at a target of interest), saccadics (the ability of the eyes to move accurately, efficiently, and rapidly from one target of interest to another), and binocular vision (the ability of the eyes to work together as a team). In large part and for a large proportion of people, inefficiency in any of these essential skills results in visual fatigue and stress associated with visually oriented tasks. It may become difficult for the eyes to aim, move and focus while working as a team, causing discomfort, loss of productivity, and less than optimal educational and/or occupational performance in general. Furthermore, the stress created by the inefficient function of these skills may contribute to the development of eyesight related problems (i.e., myopia, astigmatism). Summarizing, inefficiency in any of the essential visual skills may cause discomfort, loss of productivity, and less than optimal educational and/or occupational performance in general.
To optimize visual functioning and hopefully prevent visual deterioration, the visual system (the eyes, eye muscles and brain centers associated with vision) can be trained to work more efficiently. Vision is a skill that can be trained. The benefits of eye training are multidimensional. Among the benefits, training the eyes provides a physiological improvement in the responsiveness of the entire visual system. The eye muscles, for example, like all trainable muscles improve when properly trained. In effect, they benefit from eye training just as different, more visible human muscles benefit from other forms of exercise.
It is known that physical training improves the ability of the muscular and neurological system to respond with greater speed, accuracy, flexibility and fluidity, thereby enhancing overall performance. The same holds true for training the visual skills required for optimal visual performance. Most of the changes that take place as a function of physical training are gradual and occur over an extended period of time. The same holds true for the eyes. They adapt optimally to exercise that moderately exceeds their capacity.
Therefore, there is a continued and important need for new eye exercise devices and methods. Particularly, there is a need for eye exercise devices that are portable; use moderate levels of exercise, and that may be used to train a variety of visual functions simultaneously.
The present invention addresses these needs by providing eye exercise devices and methods that use the eye""s natural response to different colors to train the eye(s). In accordance with one aspect, the invention provides an eye exercise device that includes
a) a housing, including a plurality of colored light sources viewable by an observer and disposed in a substantially linear alignment, the colored light sources being of at least two different colors, including a first color which causes the eye to increase the focusing power of the eye to gain a sharp image of the first color, and a second color which causes the eye to decrease the focusing power of the eye to gain a sharp image of the second color; and
b) a controller for controlling the display of the light sources to an observer.
Preferably, the light sources of the first color are mounted in an alternating arrangement with the light sources of the second color. Preferably, the first color is selected from the group consisting of orange and red, and the second color is selected from the group consisting of violet, indigo, turquoise, and blue. The more preferred first color is red, and the more preferred second color is blue or violet. The preferred light sources are light emitting diodes.
The device may further include eyeglasses having interchangeable red and blue or violet filters for selectively affecting the display of the light sources. The device may also further include a control panel for adjustment of the controller.
In accordance with one embodiment, the housing is a horizontal bar, and the eye exercise device further includes a handle connected between two ends of the horizontal bar, dividing the horizontal bar into two segments, each of the segments extending from one of the ends of the horizontal bar to the location where the handle is connected. The horizontal bar has a top surface and a bottom surface. The top surface houses the light sources. The top surface of the horizontal bar may also include a linear marking extending substantially between the ends of the horizontal bar. The handle is connected to the horizontal bar from the bottom surfaces side. The preferred shape of the handle allows placement of the device in a vertical, oblique, or horizontal position with respect to a horizontal plane without additional structural elements. The preferred shape of the handle is octagonal. Also, preferably, at least one of the ends of the horizontal bar defines an open recess that is used in some of the eye exercises.
In a more preferred embodiment, the horizontal bar is foldable so that the eye exercise device may be placed in an operational position, in which the horizontal bar is substantially perpendicular to the handle, or a storage position in which the horizontal bar is folded and the two segments of the bar are substantially parallel with and laying adjacent to the handle. Preferably, the location where the handle is connected to the horizontal bar is substantially equidistant from both ends of the horizontal bar. Preferably, the light sources are also substantially equidistant from each other.
In accordance with another aspect, the invention provides an eye exercise device that includes
a) one or more first light sources of a first color that causes the eye to increase the focusing power of the eye to gain a sharp image of the first light sources,
b) one or more second light sources of a second color that causes the eye to decrease the focusing power of the eye to gain a sharp image of the second light sources, the second color being different from the first color,
c) a housing to which the first and second light sources are mounted, and
d) a programmable controller to alternate the display of the first and second light sources to exercise one or more eyes of a person by alternately causing an increase and decrease in the focus power of an eye of a human subject observing the light sources.
Preferably, the first color is selected from the group consisting of orange and red, and the second color is selected from the group consisting of violet, indigo, turquoise, and blue. The preferred first color is red, and the second color is blue or violet. In this aspect, the eye exercise device may include any of the specific features previously described above in reference to another device aspect of the invention.
According to another aspect, the invention provides a method of exercising an eye of a person that includes
a) exposing the observer to a predetermined arrangement of (i) one or more first light sources of a first color that causes the eye to increase the focusing power to gain a sharp image of the first light sources, and (ii) one or more second light sources of a second color different than the first color that causes the eye to decrease the focusing power to gain a sharp image of the second light sources; and
b) alternating the display of the first and second light sources to exercise the eye of the observer observing the light sources by alternately causing the focusing power to increase and decrease.
Preferably, the alternating includes alternating the display between the first color being selected from the group consisting of orange and red and the second color being selected from the group consisting of violet, indigo, turquoise, and blue. The preferred first color is red, and the preferred second color is blue or violet. The preferred pre-determined arrangement is a substantially linear alignment of the light sources.
In accordance with this aspect of the invention, the method further includes positioning the observer vertically in front of the substantially linear alignment of the light sources during the exercise. Preferably, the light sources and the eyes of the observer are at approximately the same level. The observer may wear eyeglasses having interchangeable red and blue or violet filters to selectively affect the display of the light sources to the observer.
In one embodiment of this aspect of the invention, the method further includes placing the light sources in such a manner that a vertical plane containing the substantially linear alignment of the light sources and a vertical plane containing an imaginary line drawn through the eyes of the observer are substantially parallel to each other. The substantially linear alignment of the light sources may be placed in a horizontal, oblique, or vertical position with respect to a horizontal plane containing the eyes of the observer. Once the observer and the light sources are situated as desired, the observer is exposed to a discreet exercise sequence. Thereafter, the distance between the observer and the light sources may be changed, and the observer may be exposed to another discreet exercise sequence. During the exercise, the light sources are preferably activated consecutively and one at a time.
In another embodiment of this aspect of the invention, the method further includes placing the light sources in such a manner that a vertical plane containing the substantially linear alignment of the light sources and a vertical plane containing an imaginary line drawn through the eyes of the observer are substantially perpendicular to each other. Preferably, the method further includes activating the light sources consecutively and one at a time.
In accordance with another aspect, the invention provides a method of exercising an eye or eyes of an observer, including
a) exposing the observer to a plurality of red and blue light sources, and
b) activating one or more of the light sources to display the light sources to the observer one-at-a-time.
Preferably, the light sources are in a substantially linear alignment. Also, the red light sources and the blue light sources are preferably mounted in an alternating arrangement with each other. In the preferred embodiment, the light sources are displayed sequentially.
In both method aspects of the invention, it is preferred to use the eye exercise devices described herein. The features, embodiments, or aspects of the eye exercise devices are suitable for use with the methods of the invention.
In accordance with another preferred aspect, the invention provides a kit for exercising eyes including
a) a device that includes a plurality of colored light sources viewable by an observer and disposed in a substantially linear alignment, the colored light sources being of at least two different colors, including a first color which causes the eye to increase its focusing power to gain a sharp image of the first color and a second color which causes the eye to decrease its focusing power to gain a sharp image of the second color; and
b) eyeglasses having interchangeable color filters of the first color and second color for selectively affecting the display of the light sources to the human subject.
Preferably, the light sources of the first color are mounted in an alternating arrangement with the light sources of the second color. Preferably, the first color is selected from the group consisting of orange and red, and the second color is selected from the group consisting of violet, indigo, turquoise, and blue. The more preferred first color is red, and the more preferred second color is blue or violet.